[time-nuts] Z3801A recovering

[Joseph Gray]

After about three hours:
https://dl.dropboxusercontent.com/u/19599147/Z3801A%203hr.png

Ignore the graph discontinuity at the beginning. I had to power cycle
to change to UTC.


Joe Gray
W5JG


On Sun, May 1, 2016 at 1:30 AM, Joseph Gray <jgray at zianet.com> wrote:
> In past discussions about replacing a 6-channel Oncore in a Z3801A
> with an 8-channel VP Oncore, some claimed that the VP had to first be
> put into 6-channel mode, others indicated this was not necessary.
> Earlier tonight, I put a VP (still in 8-channel mode) into my
> malfunctioning Z3801A. Monitoring with Z38xx, I see no signs that this
> is a problem. Even the logs look clean.
>
> In reading the VP documentation, I saw that there were several
> 6-channel commands, along with similar 8-channel commands. That is why
> I thought I'd try using the VP without setting it to 6-channel mode.
> It was an experiment that seems to have succeeded.
>
> I don't want to jinx things, but so far, my formerly flaky Z3801A is
> working normally, after replacing the GPS module. The self survey
> finished in two hours (about 25 minutes ago). The EFC and PPS TI/s
> graphs are no longer going wild.
>
> I'm going to monitor this for quite a while before I call it fixed.
> Then it's on to repairing the Z3801A that I traded for.
>
> In addition to replacing the GPS module, I also replaced three caps on
> the power supply board. On initial inspection, C108 and C110 had a
> faint white ring around them, on the PCB, as though they had out
> gassed. There was also some corrosion on pin TP104, which sits between
> C108 and C110. The caps checked fine with my LCR meter, but I thought
> I'd replace them while I had things apart. I also replaced C111, which
> is nearby. When I removed the caps, there was no corrosion on the PCB.
>
> When I inspected the other Z3801A which is awaiting repair, I saw the
> same faint white rings around C108 and C110. There was no corrosion on
> TP104, however. I will replace those caps as well, when I get to it.
>
>
> Joe Gray
> W5JG